/*
===========================================================================
This source file is part of DyLab (Dynamic Laboratory)
For the latest info, see http://dylab.googlecode.com

Copyright (c) 2006-2008 Lukas Krejci
(krejci.lukas@volny.cz)

This file is part of DyLab.

    DyLab is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    DyLab is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with DyLab.  If not, see <http://www.gnu.org/licenses/>.
===========================================================================
*/

//===========================================================================================
#include <dylab/utils/geometry/Plane.h>
#include <dylab/utils/math/Math.h>

//===========================================================================================
dylab::Math::intersection_t 
dylab::Plane::computeLineIntersection(const Vector3 & _a, const Vector3 & _b, Vector3 & _ip, 
									  bool allowAMinus, bool allowBPlus) const
{
	Vector3 dir = _b - _a;
	real_t d = mNormal.dot(dir);

	if (d == 0)
	{
		if (testPointInside(_a))
			return Math::INTERSECTION_LINE;
		else
			return Math::INTERSECTION_NONE;
	}

	real_t t = - (mNormal.dot(_a) + mDisplacement) / d;

    if (t < Math::ZERO && !allowAMinus)        
        return Math::INTERSECTION_NONE;                          

    if (t > Math::ONE && !allowBPlus)         
        return Math::INTERSECTION_NONE;

	_ip = _a + dir * t;

	return Math::INTERSECTION_POINT;
}
//-----------------------------------------------------------------------------